The first animals to reproduce through genital mashing were small fish that lived about 350 million years ago, a paper published in Nature shows. While their ancestors laid boring-old eggs, the aptly called Microbrachius dicki had sex side-by-side, linking fins so they wouldn't float apart. Aww!

Because they're such elusive creatures, scientists weren't too sure about their mating habits or what those tusks are for exactly.

But new research published in Marine Mammal Science this year shows male tusks can be indicators of their testicle size — an indicator of fertility. (Female narwhals have tusks too, but they’re smaller in size.) So ladies, the next time you see a big tusk... *winks*.

A study published in Psychological Science found that people's visual patterns concentrated more on a stranger’s face if the viewer saw the person as potential for romance. When the images made participants lusty, their gaze tended to look more at the person’s body.

Before you say “duh,” the automatic judgment can occur in as little as half a second, so it might not be perceivable.

Death by sex sounds like a good way to go, but the logistics are actually a bit horrifying. This year scientists discovered three new species of antechinus, a marsupial first found in Australia last year, that disintegrate from all the violent sex they have.

While trying to get it on with as many females as possible within a few weeks, the male antechinus' increasingly exhausted body begins to fall apart: It bleeds internally, its muscles degenerate, its immune system fails, it develops ulcers and gangrene, and its fur falls out. Sexy!

How did dinosaurs have sex? Historically scientists have twiddled their thumbs about this mystery due to it being a bit of a taboo to study and a glaring lack of evidence.

While no fossils of copulating dinosaurs have been found, in recent years scientists have started looking to dinosaurs’ closest living relatives — birds and crocodiles — to figure out how they reproduced.

Both birds and crocodiles have a “cloaca," or an opening that deals with intestinal, reproductive, and urinary tracts. Early bird species had a penis that emerged from this opening to deliver sperm, so dinosaurs probably did too.

Well, at least these two who live in a Croatian sanctuary do. In a paper published in Zoo Biology, scientists observed 28 acts of fellatio between the duo in the 116 hours that they observed them. Fancy that.

A satellite with one male and five female geckos launched so that scientists could observe their mating habits in zero gravity.

After it was lost, then found again, news broke that the space sex geckos died upon their return to Earth. The Moscow Times reported that scientists would have to go through 44 days' worth of video footage to determine exactly when they died and if they ever even engaged in gland-to-gland combat.